/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.core.plugin;

import org.apache.flink.util.FlinkRuntimeException;

import java.io.IOException;
import java.nio.file.Path;
import java.util.Collection;
import java.util.Collections;
import java.util.Optional;

/**
 * Utility functions for the plugin mechanism.
 */
public final class PluginUtils {

	private PluginUtils() {
		throw new AssertionError("Singleton class.");
	}

	public static PluginManager createPluginManagerFromRootFolder(Optional<Path> pluginsRootPath) {
		Collection<PluginDescriptor> pluginDescriptorsForDirectory;

		if (pluginsRootPath.isPresent()) {
			try {
				pluginDescriptorsForDirectory =
					new DirectoryBasedPluginFinder(pluginsRootPath.get()).findPlugins();
			} catch (IOException e) {
				throw new FlinkRuntimeException("Exception when trying to initialize plugin system.", e);
			}
		} else {
			pluginDescriptorsForDirectory = Collections.emptyList();
		}

		return new PluginManager(pluginDescriptorsForDirectory);
	}
}
